CHAPTEE XVII 



TRACHEATA 



Class I. PROTOTRACHEATA 



Onyohophoea (Peripatidea), Peripatus 



Chaeacteeistics. — Animals with soft caterpillar -like bodies, 



ivith a pair of antennae, a pair of jaws, a pair of oral 



papillae, and numerous pairs of walking legs, each hearing 



claws. Respiration hy means of tracheae, the stigmata of 



which are numerous and scattered. Nephridia present. 



The Prototracheata include a single genus, Peripatus, which 



is morphologically one of the most interesting animals known ; 



its developement, made known to us chiefly by the researches 



of Sedgwick, is also of the highest morphological import, 



and our recently-acquired knowledge of it has solved many 



problems of Arthropod structure. Its distribution is also 



interesting ; it has been found in New Zealand, Australia, the 



Cape of Good Hope, South America, the West Indies, and 



possibly in Sumatra. 



Peripatus capensis is a very beautiful-looking animal, of a 

 velvety green colour dorsally, shading off into an orange-brown 

 on the under surface. The female is larger than the male, and 

 when adult may measure 65 mm., the male being about three- 

 quarters as long. The skin is thrown into numerous ridges, 

 which are beset with a number of papillae, each bearing a spine. 



Appendages of Peripatus capensis. 



1. Antennae. 



2. Jaws in buccal cavity, armed with two cutting blades. 



3. Oral papillae, with orifice of slime glands. 

 4-20. Seventeen pairs of clawed walking-feet. 



21. Anal papillae. 



